large integers, the first inserted value would always create
an 'or X, 0'. Even though this is trivially zapped by
instcombine, don't bother creating this pointless instruction.
llvm-svn: 106979
the returned value after the tail call if it differs from other return
values. The optimal thing to do would be to introduce a phi node for
the return value, but for the moment just fix the miscompile.
llvm-svn: 106947
if-conversion. The RemoveExtraEdges function doesn't work for blocks that
end with unanalyzable branches, so in those cases, the "extra" edges must
be explicitly removed. The CopyAndPredicateBlock and MergeBlocks methods
can also avoid copying successor edges due to branches that have already
been removed. The latter case is especially helpful when MergeBlocks is
called for handling "diamond" if-conversions, where otherwise you can end
up with some weird intermediate states in the CFG. Unfortunately I've
been unable to find cases where this cleanup actually makes a significant
difference in the code. There is one test where we manage to remove an
empty block at the end of a function. Radar 6911268.
llvm-svn: 106939
CopyFromReg nodes for aliasing registers (AX and AL). This confuses the fast
register allocator.
Instead of CopyFromReg(AL), use ExtractSubReg(CopyFromReg(AX), sub_8bit).
This fixes PR7312.
llvm-svn: 106934
introduced in r106343, but only showed up recently (with a particular compiler &
linker combination) because of the particular check, and because we have no
builtin checking for dereferencing the end of an array, which is truly
unfortunate.
llvm-svn: 106908
The VNInfo.kills vector was almost unused except for all the code keeping it
updated. The few places using it were easily rewritten to check for interval
ends instead.
The two new methods LiveInterval::killedAt and killedInRange are replacements.
This brings us down to 3 independent data structures tracking kills.
llvm-svn: 106905
SCEVUnknown values which are loop-variant, as LSR can't do anything
interesting with these values in any case. This fixes very slow compile
times on loops which have large numbers of such values.
llvm-svn: 106897
for an "i" constraint should get lowered; PR 6309. While
this argument was passed around a lot, this is the only
place it was used, so it goes away from a lot of other
places.
llvm-svn: 106893
are dead, not just the def of this register. I.e., a register could be dead, but
it's subreg isn't.
Testcase to follow with a subsequent patch.
llvm-svn: 106878
with the following instructions. This is done via trickery by considering the
instruction preceding the IT to be the hazard. Care must be taken to ensure
it's the first non-debug instruction, or the presence of debug info will
affect codegen.
Part of the continuing work for rdar://7797940, making ARM code-gen unaffected
by the presence of debug information.
llvm-svn: 106871
Gabor Greif